How do you use tracking codes ?

Hi guys,

I was wondering what was the best way to use Pardot campaign tracking code. I've read on a few websites that it could be implemented in the header code but how do i manage that ?

Do i need to add EVERY campaign tracking codes on the header or wouldnt it be more practical to put it only on the concerned pages ?

My example here is : I've created a landing page campaign ; its seems more logic to me to put the code only in this landing page than in the header, am i right ?

If you have any good practices about tracking code, i'll be glad to hear them !